Analog-to-digital converters have been formed in a variety of architectures. Conventionally, these architectures have been implemented with transistors. For example, one common implementation includes a cross-coupled pair of transistors. However, there are several disadvantages associated with using transistors to implement an analog-to-digital converter.
First, devices used in digital circuits are becoming smaller. As these devices decrease in size, quantum mechanical effects begin to appear. The electrical properties of conventional transistors may be unacceptably by quantum mechanical effects. Secondly, a transistor-implemented analog-to-digital converter is limited by the switching speed of the transistors, which may be too slow for some applications. Finally, conventional transistors are limited to two stable states. Thus, systems using transistors typically may only convert analog signals into binary digital signals, making the use of multi-valued logic difficult.